1. Field of the Invention
The present invention relates to a hair protection film for cold permanent wave treatment, which film facilitates winding of the hair around curling rods and prevents bending of the hair.
b 2. Description of the Related Art
A treatment agent used in a widely practiced cold permanent wave treatment consists of a reducing agent (first liquid) of an alkali solution prepared by adding an alkali agent to a main agent of thioglycolate or salts thereof; and an oxidizing agent (second liquid) consisting mainly of a bromate.
The hair is wound around curling rods to a desired style. The first liquid is applied to the hair to swell the hair by the action of the alkali agent contained in the first liquid, thus helping the main agent comprising thioglycolate to permeate the hair. The thioglycolate permeated in the hair cuts, by reduction, cystine bonds of polypeptide (protein) constituting the cortex of hair. The cystine bonds are displaced to fit the hair to the curling rods. Then, the second liquid is applied to the hair, whereby the cut cystine bonds are formed once again in the state wherein the cut bonds have been displaced. Thus, the waves of hair are fixed.
However, the degree of damage of the hair, due to ultraviolet rays, previous cold permanent wave treatments, and the like, increases towards the tip of the hair. In addition, the cuticles covering the surface portion of hair may be peeled and damaged, the cortices of hair under the cuticles and the matrix filled between cortices may be exposed, or the matrix may flow out. The degree of these undesirable conditions increase towards the tip of hair.
Accordingly, if the damaged hair and the less damaged proximal portions of hair and newly grown hair are treated by the first liquid under the same conditions, the damaged hair is considerably affected and further damaged by the first liquid and shrunken owing to lost of moisture.
Using a method involving applying a cold permanent wave treatment to damaged hair, it is known to subject the hair to a pretreatment process, before it is wound around curling rods. In the pretreatment process, a treatment liquid consisting mainly of PPT (polypeptide, which is protein) is applied to the particularly damaged distal portions of hair (about 1/3 from the tip), thereby reducing the strong influence of the first liquid and preventing shrinkage of hair. In addition, in order to wind the hair, wetted with the treatment liquid, around curling rods smoothly and neatly, without bending the tip of hair, the distal portions of hair, before wound around the rods, are wrapped with hair protection films of Japanese paper or nylon films.
Recently, a first liquid of acid solution consisting mainly of thioglycolate or a salt thereof has been developed and substituted for the above-mentioned first liquid of alkali solution. The first liquid of acid solution has been used similarly with the first solution of alkali solution.
In the prior art, the treatment liquid and hair protection films are used to reduce the strong influence of the first liquid for cold permanent wave treatment, thereby preventing shrinkage of hair and facilitating the winding of the hair around the curling rods. However, there are the problems: the cuticles are peeled and damaged, the damaged hair wherein the matrix between cortices has flown out is not recovered, and the damage to hair due to newly applied cold permanent wave treatment is neither prevented nor recovered, as a result of which the degree of damage to hair is aggravated.
Since additional steps are required of applying the treatment liquid to the hair in advance and winding the hair, wetted with this liquid, around the curling rods, the permanent wave treatment process is complicated.
In addition, the first liquid of acid solution is developed and used to lessen the damage due to the first liquid of alkali solution; however, the hair already damaged by the first solution of alkali solution, ultraviolet, etc. is not recovered even if the first liquid of acid solution is used.